The present invention relates to floorings.
Floorings of the type specified above have, over the years, found extensive use in a very wide range of applications. A particularly extensive sector of use is that of floorings for sports and athletics facilities, the two terms xe2x80x9csportsxe2x80x9d and xe2x80x9cathleticsxe2x80x9d being here used in their widest acceptation, i.e., also comprising installations such as gymnasia or fitness centres or medical centres, surgeries for carrying out medical examinations on sportsmen, etc.
FIG. 1 represents an ideal vertical cross section of a flooring according to the prior art. In particular, it is the flooring sold under the trade name SPORTFLEX SUPER X(trademark) by the present applicant.
The flooring in question consists of a generally laminar or sheet-like 1, in which it is possible to distinguish:
a treading layer 2 designed to face upwards in normal conditions of laying of the flooring 1; and
an ensemble of supporting formations 3, in general presenting a structure that may be defined as pedunculate.
In practice, the flooring 1 is made, for example, starting from mixtures of isoprene rubber by means of one or more cascaded calendering operations. In this way it is possible to provide on the upper face 4 of the treading layer 2 with a generally corrugated pattern, which is primarily aimed at providing a non-slip surface. The ensemble of supporting formations 3 usually takes the form of a reticulated-type structure comprising one first array made up of a series of ribs 5 connected together by a second array formed by respective ribs 6, which are orthogonal to the former ones and which basically resemble formations that extend like bridges connecting adjacent ribs 5.
In the specific solution according to the prior art illustrated in FIG. 1, the height or depth of the bridges 6 (with respect to the general plane of extension of the treading surface 2) is slightly smaller than that of the ribs 5.
The characteristics of a flooring of the type described above can be identified in a quantitatively precise way by resorting to the elastic impact test according to the DIN 18035/6 Standard. This standard, in agreement with the DIN 18032/2 Standard, makes it possible to define a parameter, referred to as KA (abbreviation of the German word Kraftabbau), which substantially corresponds to a characterization, in percentage terms, of the behaviour of the flooring subjected to the fall of a weight of standard dimensions with respect to the behaviour of a rigid plane, typically a cement floor, when subjected to the same impact.
The floorings designed to be used in gymnasia generally have a KA coefficient of between 15-20% and 30-50%. The lower value of the aforesaid range corresponds to a flooring that can be characterized as rather xe2x80x9chardxe2x80x9d, whereas the upper limit corresponds to a flooring that proves somewhat xe2x80x9csoftxe2x80x9d in regard to the loads to which it is subjected.
In EP-A-0 913 524, a flooring is described which, re-proposing a structure that is basically similar to the one illustrated in FIG. 1, is characterized in that at least some of the supporting formations namely, the ribs 5) extend with their respective direction of extension monotonically oblique (usually at an angle of between 25xc2x0 and 50xc2x0 approximately) with respect to the plane of the treading layer 2.
In this way, it is possible to make a flooring that presents characteristics of compliance with respect to the stress exerted by an athlete who is running on a flooring that is differentiated according to the direction in which he is proceeding.
The present invention deals specifically with the problem of making a flooring of the type currently preferred to as xe2x80x9cfree laidxe2x80x9d, i.e., a flooring designed to be applied on a substrate without the application of means of adhesive connection to the substrate itself. It may, for example, be a flooring designed for being laid in a gymnasium without a specific preparation of the foundation (for example, because it is laid on an underlying flooring) and/or because the aim is to have available a flooring which, if desired, can be removed. To provide a concrete example, it may be a flooring that is generally soft, and hence with high compliance, designed for being temporarily laid, for carrying out particular exercises or types of sports, on an underlying floor that is generally hard or rigid (for instance, a playground for playing basket ball or volley ball).
A typical problem linked to the use of free-laid floorings is related to the need for ensuring a sufficiently firm anchorage of the flooring on the substrate in order to prevent, for instance, the flooring (which is not adhesively anchored to the substrate) from sliding with respect to the substrate when subjected to loadings according to the principal direction of extension.
To overcome this drawback, it is possible to think of configuring the formations for supporting the flooring in the form of sucker-type structures making up an array of small feet designed to support and anchor the flooring to the substrate.
This solution, however, presents three fundamental drawbacks.
In the first place, the elements acting at the same time as feet and as suckers, with their discretized distribution, exert an action of support likewise discretized for the treading layer. When the latter is, as frequently occurs, quite soft and compliant in itself, the result is that the person walking on the flooring wearing rather light footwear or in bare feet clearly perceives the presence and discrete distribution of the supporting feet underneath the flooring.
In the second place, this solution presents the drawback of offering a good resistance to the undesired sliding of the flooring on the substrate only as long as a very high percentage of feet/suckers are performing the desired function of anchoring the flooring to the substrate. If, for any reason (for example, owing to the undesired lifting of an edge or a corner of the flooring, if accessible), a substantial percentage of the feet located there lose the sucker-type relationship of co-operation with the substrate, there exists a high likelihood of this phenomenon rapidly extending towards other areas of the flooring as soon as an appreciable sliding stress takes place.
A third drawback is linked to the fact that the characteristics of anchorage to the substrate, provided basically by the characteristics (shape, size, and distribution) of the feet functioning as suckers, play an important role in establishing the degree of compliance of the flooring, so that this degree of compliance ends up by being affectedxe2x80x94frequently in an undesired wayxe2x80x94by the characteristics of connection to the substrate that it is intended to achieve.
The object of the present invention is to provide a flooring of the type specified above having characteristics of a free-laid flooring in which the above-mentioned problems are overcome.
According to the present invention, this object is achieved thanks to a flooring having the characteristics specified in the following claims. The invention also regards the corresponding process of fabrication.